Hierarchical porous carbon microrods derived from albizia flowers for high performance supercapacitors

In this work, we report the successful synthesis of hierarchical porous carbon microrods via a one-step pyrolysis and activation treatment at different temperatures. The optimized porous carbon microrods have many advantages, including high specific area (2757.63 m2 g−1) with a total pore volume (1.47 cm3 g−1), high self-doping N contents, and unique porous microrod structure. As a result, the optimized porous carbon microrods show a fairly high specific capacitance of 406 F g−1 at 0.5 A g−1 (335 F g−1 at 10 A g−1) in 6 M KOH electrolyte and a good rate capability of 86.1%. Furthermore, the symmetric supercapacitor of porous carbon. microrods with 1 M Na2SO4 electrolyte exhibits a high energy density of 26.3 W h kg−1 at a power density of 429 W kg−1. The symmetric supercapacitor also shows excellent cycle ability with a capacitance retention of 94% over 10,000 cycles. This study provides a valuable approach for preparation of electrode materials for energy storage systems by using abundant biomass.